1. Field of the Invention
This invention relates to a combination for sealing loose, bulk material against downward movement on an inclined conveyor, and in particular at the material transfer point from a discharging or feeding conveyor or other such device onto an apron conveyor having pusher elements.
2. Description of the Prior Art
Design of inclined conveyors and conveyor systems must necessarily address the inherent problems associated with the propensity of conveyed material, particularily when handled in bulk, unpackaged, unstructured form, to slide down the upward moving conveying surface. In the past this problem has been addressed by arranging conveying systems so the slope of the incline is shallow enough to avoid the backflow tendency. This approach requires lengthier conveyors and corresponding greater floor space dedicated to such use than would otherwise result could the problem be resolved by other means. The use of pushers on the conveying surface is a known attempt to resolve the problem by a mobile damming approach. But at the critical transfer location where material from an overloaded device discharges onto a second and inclined conveyor, a cascade effect results which pushers have been ineffective in preventing.
Solid waste management systems are particularily troublesome with regard to the sealing problem at the foot end of inclined conveyors where the loose, diverse unwieldy waste matter is deposited. Conveyors used in waste treatment plants must transport the material before processing begins from a receiving station, generally to a shredder, where it is pulverized to produce a more homogenous size, a requisite of successive processing steps.
The initial conveyor run in the course from the receiving station to the shredder is usually along a horizontal conveyor often loaded with a depth of eight to ten feet of waste material upon the conveyor surface. This conveyor travels at a slow rate of speed relative to the inclined conveyor onto which the mounded matter is allowed to fall naturally. The speedier inclined device will produce the effect of reducing the material depth to a more tractable and uniform height, preferably approximating the pusher height above the conveyor surface. In this way, the pusher elements will maintain the material in position of the conveyor in the course of vertical travel.
Because of the tremendous quantities of refuse processed daily at plants of this type, it is especially important to contain the material completely during the operating cycle against errant motion. Continual escape of material discharging from one conveyor, if allowed to proceed unabated, will quickly mound up at the foot of the receiving conveyor with the result that operating safety and efficiency are soon reduced beyond tolerable levels. The magnitude of the problem is such that given the volume of the material handled, even granular substances contained in the refuse, if allowed to bypass the receiving device, will accumulate at its foot at such a rate as to require shutdown and removal several times during a workday.
Granular matter in the form of broken glass, sand, etc., is especially difficult to seal against when intermixed, as it always is, with sizable refuse such as tree limbs, auto parts, paper, furniture, etc. The invention disclosed herein is an efficient, reliable solution to the problems discussed.